Prior to Sierra, I've always been able to spawn a helper that needs true UID under Python via the sudo "sudo -S" mechanism. This has worked since OS X 2.5. However, on a fresh Sierra system, that mechanism no longer works and my task is held because it's now waiting on either user interaction in response to a "password: " prompt or a "no tty detected" error.
The manpage for sudo still states:
-S, --stdin Write the prompt to the standard error and read the password from the standard input
instead of using the terminal device. The password must be followed by a newline
character.
However, this no longer works under Sierra.
Is this a documentation failure or is sudo broken in Sierra? If a documentation error, how should we expect sudo work for non-tty tasks?